Legitimacy has become an increasingly important topic within international law. The reasons behind this recent surge in the interest of the justification of authority are intimately related to the transformations that the international legal order is undergoing. From a consensual normative order, centred on interstate relations, international law has evolved into a complex and dense normative framework encompassing subject areas that until recently seemed alien to international law. The increasing influence of international law has sparked an intense discussion about the suitability of the conventional basis of its legitimacy. In particular, due to the direct impact on individuals of international legal norms in areas previously covered by national law, a legitimacy gap has opened up, making the legitimation of international law a pressing concern. This dissertation offers a critical account of legitimacy and its use in international law. On the conceptual side, the dissertation illustrates the broadness of the concept and analyses some of the reasons for why legitimacy is highly contested and why these disagreements are unlikely to disappear. On the descriptive side, the thesis questions the often-presumed link between legitimacy and the stability of a social arrangement - the international legal order in this case - by examining alternative explanations and by contesting the idea of legitimacy as a matter of individual beliefs. As a way forward, the dissertation offers an alternative reading of legitimacy, which proposes a shift of focus from legitimacy to legitimation, moving from a static to a dynamic perspective. In contrast to existing explanations, this account is not centred on ascertaining whether a certain social arrangement is legitimate or not, but rather on describing and analysing the means through which actors attempt to expand or restrict the permissible boundaries of action.

LC Subject Heading: International law; Effectiveness and validity of law